So-called minimally invasive surgery has become increasingly popular in a variety of surgical procedures. Minimally invasive surgery typically involves introducing surgical devices into a patient through small access incisions, in contrast to obtaining full and open access to the surgical site through large incisions.
Briefly, minimally invasive surgery is typically carried out through one or more relatively small incisions, which are usually between approximately 1/2 and 11/2 inches in length, and through which an entry tube or trocar is placed. Optical and medical instruments are inserted through the trocar(s) to allow the physician to view the surgical area and to target the organ or tissue that is the subject of the surgery, and then to carry out the desired surgical procedure. Because of the relatively small diameter of the trocar(s), however, withdrawal of the target tissue therethrough can be difficult, particularly if the tissue is dense or muscular, such as a kidney, uterus or uterine myoma.
One previously accepted technique for removing such tissue required manually cutting the tissue into smaller pieces within the body cavity, which pieces were then removed through the trocar by graspers. This procedure, however, in addition to being very tedious and time consuming, also suffers from a number of other possible drawbacks, including possible excessive bleeding, possible accidental cutting of other tissue and possible contamination of the abdominal cavity with target tissue.
A morselation device is described in U.S. Pat. No. 5,290,303. That device uses an inner rotating tube and an outer stationary sheath, the inner tube extends beyond the sheath and has a tapered end for severing tissue. A further outer tube or shield may also be used over the sheath. This device may be used with a tissue bag, such as shown in U.S. Pat. No. 5,037,379. The tissue to be morselated may be placed in the bag and the device inserted into the bag to carry out the morselation within the pouch.
One of the concerns with the device shown in the '303 patent is possible puncture of the pouch by the rotating tube, with accompanying potential contamination of the anatomical space, as well the time consuming insertion and placement of a new pouch within the body cavity. Although the bag disclosed in the '379 patent has two layers, including a puncture resistant inner layer, the above-mentioned concern is still present. In addition, the multi-layer construction with a higher strength inner container may make folding and insertion of the pouch into the abdominal cavity more cumbersome.
More recently, in U.S. Pat. No. 5,304,124, an apparatus and method were disclosed for removing a uterine myoma. In that method, a tube is inserted through the trocar and into the myoma. A wire loop, which may energized by radio frequency energy, is located at the distal end of the tube to cauterize the tissue as the tube is inserted into the myoma, resulting in a core of tissue being located within the tube. A separate morselator is then inserted into the tube to cut up the tissue (such as by rotary blades, laser, or a rotary whip), and the morselated tissue is then evacuated. Although such a procedure may be an advance over a purely manual procedure, this procedure is still relatively complicated, requiring separate steps and apparatus to core and to morselate the tissue.
In addition, the procedure described in the '124 patent, when utilized with radio frequency ("RF") energy, uses a separate grounding or return electrode or antenna in contact with the skin of the patient, for example, that the patient lies on. As is well known in the art, such an application of RF energy has certain shortcomings. It requires the energy to travel between the electrodes, a relatively long distance through the body, with possible adverse effect on other body tissue. It also may result in accidental injury to non-target tissue, for example, if the active electrode is inadvertently brought into contact with non-target tissue. Also, this patent discloses a relatively complex mechanism to sever the tissue core from the myoma.
Accordingly, it is a general object of the present invention to provide apparatus and methods for removing target tissue through a trocar, which apparatus and method are more simplified and/or easier to use than the apparatus and method described above, and reduces the risk of accidental injury to non-target tissue.